For the shipping of groups of diverse products corresponding to different orders, containers made of cardboard or similar materials are being used more and more at the present time, containers such as American boxes or American half-boxes, trays, etc . . . onto the bottom of which the central part of a section of heat shrinkable plastic film is glued, the end parts of which are left free in order to be able to be folded over the products grouped together in the container following preparation of an order. After placing the group of products in the container, the container is passed through a shrinking tunnel and the plastic film then shrinks onto the products holding them firmly in place inside the container, which avoids having to use additional fixing elements.